Wet plug for well pipes



Aug. 5, 1952 c. J. M COY WET PLUG FOR WELL PIPES 2 SHEETSSHEET l FiledJune 2 1949 li lil I 1 IVEN TOR. @994 a. MCCOJ ,QNCwA/EVS Aug. 5, 1952,c. J. MCCOY WET PLUG FOR WELL PIPES 2 SI-IEETS-SI-IEET 2 Filed June 24,1949 M! a z m a m INVENTOR.

HTTOQNEVS' Patented Aug. 5, 1952 UNITED STATES. PATENT OFFICE I i 7 i2,605,847; f

WET PLUG FOR WELL PIPES" V can J. McCoy, Orcutt, Calif.- ApplicationJune 24, 1949, Serial No."101;041

13 Claims. (01. 166-14) This invention relates to the art of producingpetroleum from wells and is particularly directed to improvements inapparatus employed for removing eduction tubing fromjthe' well holewhile the tubing is full of well fluid.

Conventional, pumping; apparatus for petroleum wells includes a pump atthe lower end of the eduction tubing and a sucker rod which extendsthrough the eduction tubing to the surface. The sucker rod isreciprocated within the tubing to actuate the pump for lifting the wellfluid to the 'surfacerfIt is necessary from time to time towithdraw theeduction tubing from the well for the purpose of servicing or replacingthe pump. [If the pumphas become sanded up during use or has beenrendered inoperative for any reason the well fiuid may remain in theeduction tubing as it is withdrawn upwardly from the well hole.- As theeduction'tubing is withdrawn lengths thereof are disconnected section bysectionand stacked on end within the derrick. When the threadedconnection between adjacent sections is broken oil within the lower partof the tubing may be forced out by gas and spread over the derrick floorand the working crew, thereby creating a fire hazard and making the taskof withdrawingthe eduction tubingdifficult and unpleasant; I

Even after an upper section oi the eduction tubing has been disconnectedand set aside, gas formerly dissolved within the well fluid may bereleased by the reduction in pressureon the well fluid and causethe wellfluid within the lower portion of the eduction tubing -to surge byheadsif To avoid undesirable surging and consequent drenching of thederrick floor with petroleum it has been the conventional practice toscrew a conventional plug in the uppermost coupling of the lower portionof the eduction tubing as soon as an upper section is disconnected andremoved. The operation of placing the plug I in position andscrewing itinto the threads must be accomplished rapidly and effectively before asurge or head? occurs. If the plug is crossthreaded'orotherwise-inseourely attached before a surge occurs'the force of thewell fluid against of threads and whichrequires only a minimum of timeto place in position. Furthermore, I provide means for venting the gaspressure away while retaininggthe oil Within the eduction tubing. Thedanger of spraying petroleum over the derrick floor ;and working crewoccasioned by surging within the lower part of the eduction tubing istherefore largely eliminated. The wet plug embodying my invention isattached to the upper end of each eduction tube section in turn forminga seal against escape of well fluid but permitting escape of gas. A ventvalve is incorporated into the device which'is moved to closed the plugmay disengage it and the operator may i be injured if the plu Shouldstrike him. .This hazard connected with the operation of screwing theplug into position-often causes-the operator to attempt to hurry theoperation unduly with the results that the plug is cross-threaded or isjammed in thef'coupling. I I I In accordance with my invention I providea new and improved wet plug device which may readily be installed"without careful alignment position by the action of liquid movingupwardly within the'eduction tubing but is uneffected by gas pressure.Accordingly, the gaswithin the upper portion of the eduction tubing isvented away but when oil approaches thewet plug at the upper end-of thetubingthe gas venting valve is automatically closed to prevent escape ofoil. Accordingly, it is the principal object of my invention to providea new and improved form of wet-plug for use in connection with the withdrawal of eduction tubing from a well hole.

Another object is to provide a device of this type: which automaticallyvents on gas within the tubing-but which prevents escape of oil.

Another object is to provide such a device which maybe readily andrapidly secured to the upper openend of the eduction tubing with aminimum of care-in alignment.

Other and more detailed objects and advane tag'es will appearhereinafter.

In the drawings: Figure 1 is a side elevation principally in10ngitudinal section showing a preferred embodieduction tube for a well.

Figure 2' is a sectional plan view taken substantially on the lines 2-2as shown in Figure 1.

Figure 3 is a partial sectional view showing a modified form of myinvention.

Referring to the drawings the eduction tubing generally designated [0extends into a well bore (not shown). The tubing may be formedof aplurality of tubular sections connected by threaded couplings, I I.Eachof the couplings is providedwith the usual internal pipe threads l2.As the eduction tubing 10 is raised from the well it. isunjointedfsection by section and the couplings l is commonly remain onthe upper ends of the sections rather than the lower ends as thesections are set aside.

In accordance, with my. invention a wetplug assembly generallydesignated I3 is adapted to be inserted into the upper open end of thecoupling II. The assembly I3 includes a body I4 having a downwardlyextending conical skirt I5. The body is provided with a central openingI6 for slidable reception of the sleeve I1. The lower end of the sleeveI1 is provided with a flared portion I8 having a flange I9 at itsextreme end. A resilient packing ring 20 is mounted on the flaredportion I8 between the flange I9 and the lower end of the skirt I5. Aseries of annular serrated rings 2| is provided on the flared portion ISabove the position of the sealing ring 20 and p a plurality of toothedrollers are rotatably mounted on the body I4 and arranged to mesh withthe serrations 2 I. The teeth of these rollers 22 engage the threads I2within the upper end of the coupling II and the action of the serrations2I is to prevent rotation of the toothed rollers 22. The rollers 22 mayeach be provided with integral laterally extending trunnions 23 receivedwithin horizontal recesses 24 provided on the skirt I of the body It.Each of the toothed rollers 22 is therefore capable of rotating aboutthe axis of the trunnions, 23 and alsom ay have limited radial movementas the trunnions slide within the transverse recesses 24-. If desired,spring means (not shown) may be employed for normally urging the rollers22 to move, in a radially outward direction. V V

A detent ring :25 may be provided on the sleeve I? if .desi-re dpand oneor more spring urged balls 26 may enter the detent rin 25 to maintainthe sleeve I! in its raised position. A coupling collar 21 connects theupper end of the sleeve IT to the valve body 28. A valve member 29' isslidably mounted within the central axial opening 33 in the valve body28. The valve member 29 is provided with'a reduced portion 3| betweenits opposed ends so that in one position of the valvemember 29 the bodyports 32 and 33 are placed in communication, and in another position ofthe; valve member 29 the ports are isolated. Thus when the valve member23 is in the position. shown Figure 1, gas within the sleeve Il may passupwardly through the port 32 into the bore of the valve body 28. The gasmay then escape throughrvent ports 33 to the atmosphere. I If the valvemember 29 is raised so that the lower cylindrical portion thereof closesthe innerends of the ports 32, gas within the sleeve I'I cannot-reachthe central bore 30 and hence cannot escape through the vent ports 33.

The "valve member 29 or'valve head may be secured by any convenientmeans to an actuating rod or tube 34 which extends axially into theinterior of the sleeve IT. A hollow float 35 is secured to the lower endof the tube 34 by any convenient means such as,rfor example, the threads38 and lock nut 31. From this description it will be understood thatvertical movement of the float 35 within the sleeve II acts 7 4 a sideport 34a and the valve member may have a bore 2% therethrough.

In the operation of the device the wet plug assembly I3 is inserted intothe upper end of the coupling II as soon as the pipe section formerlythreaded into the threads I2 has been disconnected and set aside. Whenthe assembly I3 is installed in position the sleeve I1 is in itslower-position with the shoulder 40 on the coupling collar 21 inengagement with the shoulder H defined by the upper surface of the bodyI4. In this position the flared portion I3 at the lower end of thesleeve I'I extends downwardly below the lower end of the skirt I5 sothat the resilient sealing ring 20 contracts radially. The assembly I3may be inserted quickly and easily into the upper end of the coupling IIwithout any alignment of threads or careful manipulation. When theshoulder 42 on the underside of the body I l engages the upper end ofthe coupling. IL: the ember grasps the handle 39 and raises the sleeveI1 upwardly. This action forces the toothed rollers" 22: into engagementwith the threads I2" and. into engagement with the annular serrations.2I, abruptly locking the assembly I3 inposition within the couplingII-. Formation. gas formerly. dissolved in the well fluid and releasedtherefrom. by relaxation of pressure on the well fluid is vented outthrough the ports 32 and 33 so long as the float stremains in its lowerposition. In the event of a surge or head? of oil within the eductiontubing I0, the liquid oil raises the float 35 against the action of.gravity and moves the valve head 29 to shut oii" the vent ports beforeany appreciable quantity of oil. can escape through port 33. Floodingofthe derrick floor andfcrew with oil is thereby prevented. When thesurge or head subsides the float 35,-desce'nds by gravity and again actsto vent gas to theatmosphere. The assembly I3 is not blown out ofposition by the pressure of the oil and gassinoe the toothed rollers 22prevent upward movement 'of the as sembly I3. I'he seal ring 20 preventsescape of well fluid upwardlyalong the threads I2 in any appreciablequantity.

After the wet plug assembly I3 has been placed in operative position,and after the sleeve IT has been raised to lock it against displacement,the well crewraises the eduction tubing Ill in the normal conventionalmanner. This ordinarily entails the use of an elevator which engagesunder thelower shoulder 43 of the coupling -II. The wet plug assemblyremains in the coupling II as it is raised upwardly within the derrickand until the next succeeding joint in the eduction tubing isdisconnected. At the time-of such subsequent disconnection the float 35.acts'to vent thespace within the sleeve I! and within the uppersect-ionlof the eduction tubing so that well fluid is not retainedwithin the .upper section by suction pressure. As soon as the lowerthreaded coupling is disconnected, another wet plug assembly which is aduplicate of that shown and described is inserted into the lowercoupling. Theassembly I3 on the upper end of the pipe section justdisconnected is then removed from its-operative position and lowered tothe derrick floor'by means of a line attached to the bail M. The bail 44may conveniently be attached to the body by means of the pivot pins 45.

As the eduction tubingisv raised anddisconnected section by section thetwo wet plug assemblies I3 are used alternately so that the upper nd ofthe eduction tubing is kept closed except for the very short intervalafter the threaded connection is broken and before the wet plug assemblyI3 is installed in position. The construction of the vent valve assemblyincluding the parts 28 and 29 is such that the valve is substantiallybalanced and the pressure of the gas within the sleeve I! has no effecton the opening and closing of the valve.

In the modified form of my invention shown in Figure 3a plurality ofradially slidable dogs 50 replace the toothed wheels 22. Each of thesedogs is received within a recess 5| provided on the skirt I561. Theextending end 52 of each of the dogs is serrated to engage the teeth [2in the coupling II and the inner end 53 of each dog is tapered to restagainst the flared portion I8a of the sleeve Ila. The sealing ring 29ais positioned on the lower end of the flared portion I81; and issupported by the annular flange ISa. Retraoting springs 54 may beprovided for each of the dogs 50 so that the serrated faceof the dog ismoved out of engagement with the threads I2 when the sleeve Ila islowered with respect to the body [4a. The operation of this form of myinvention is substantially the same as that previously described inconnection with Figures land 2. In both of these forms of my inventionthe pressure of the gas and well fluid within the eduction tube tends tohold the wet plug device in position, and therefore the greater thepressure the tighter is the plug secured.

Having fully described my invention, it is to be understood that I donot wish to be limited to the details herein set forth, but my inventionis of the full scope of the appended claims.

I claim:

1. In a wet plug assembly for insertion into a threaded coupling on theupper end of an eduction pipe in a well, the combination of a bodyhaving a skirt thereof adapted to extend into the threaded coupling, asleeve slidably mounted within the body and provided with a flaredportion projecting below said body, rotary locking elements cooperatingwith the flared portion and adapted upon relative axial movement of theskirt and sleeve to engage the threads of the coupling, a resilientsealing ring encircling a portion of the sleeve, said sealing ring beingexpandible into engagement with said threads upon relative movement ofthe body and sleeve in a direction to actuate the locking elements.

2. A plug structure for temporary placement in the internally threadedupper end of eduction tubing, involving: a body member adapted to engagethe upper end of an eduction tube and including a skirt depending intothe internally threaded end thereof; a sleeve slidably mounted withinsaid body member and terminating in a flared end projecting below theskirt of said body member; an annular seal ring interposed between thelower extremities of said skirt and sleeve and adapted to expandradially on upward movement of said sleeve in said body member to sealagainst said internal threads; and toothed radially movable lockingmembers carried by said body member and engageable by the flared portionof said sleeve to interlock with said internal threads of the eductiontube on upward movement of said sleeve in said body member.

3. A plug structure for temporary placement in the internally threadedupper end of eduction tubing, involving: a body member adapted to engagethe upper end of an eduction tube and including a skirt depending "intothe internally threaded endthereof;' a sleeve'slidablyxmounted withinsaid body-member and terminating in -a flared end projecting below theskirt of. saidbody member; an annular seal? ring-interposed between thelower extremities .:of said skirt and sleeve and adapted toexpandradially on upupper extremity of"said =sleeve for. ventin as from saideduction itubing; and a float member suspended within said sleeve forclosing said valve on rise of liquid into said sleeve.

4. A.plug structure'a's' set forth in claim 2 wherein said lockingmembers are toothed wheels and the flared portion of said sleeve isequipped with teeth to engage said wheels.

5. A plug structure as set forth in claim 2, wherein: said lockingmembers are radially guided and slidable dogs having teeth in theirradially outer ends, and their radially inner ends being engageable bythe flared portion of said sleeve.

6. A plug structure as set forth in claim 3 wherein: said lockingmembers are toothed wheels and the flared portion of said sleeve isequipped with teeth to engage said wheels.

7. A plug structure as set forth in claim 3 wherein: said lockingmembers are radially guided and slidable dogs having teeth in theirradially outer ends, and their radially inner ends being engageable bythe flared portion of said sleeve.

8. In a device of the class described for closing the upper internallythreaded end of an eduction pipe in a well, the combination of a bodymember, a sleeve member slidably mounted with respect to the bodymember, locking elements carried on the body member and movable intoengagement with the internally threaded element at the upper end of theeduction pipe, a seal ring on the sleeve member adapted to engage withinthe internally threaded element, operating means on said sleeve memberfor moving said locking elements radially and expanding said seal ringinto operative position upon relative axial movementof said sleeve andbody members, a vent valve on one of said members, and a floatoperativelyconnected to close the valve in the event that well fluidshould rise in the eduction pipe.

9. In a device of the class described for closing the upper internallythreaded end of an tive axial movement of said sleeve and body members.

10. A device as set forth in claim 8, wherein:

adapted to forcefti'd wheels: to: fint'ermesh with. 1

the internal screw threads of said eductio'n, pipe. 1 2.Adeviceaszsetidrth in claim 8, wherein: said lo'cking 'elementsi aredogs. supported f'cr radially sli'dable movement by said bodymember,said dogs havingmteetlr at-their radially outer ends for meshing. withthe'internal screw threads of said eduotion pipe, and whereby saidoperating: means includes a tapered portion engaging the radially innerends ofjsaid dogs;

13. A device as set forth in claim 9, wherein: said locking elements aredogs supported for radially slidable movement by said body member, saiddogs having teeth at their radially outer ends for meshing withrtheinternal screw threads of said eduction pipe, and whereby said operatingmeans includes a tapered portion engaging the radially inner'ends ofsaid dogs.

CARL J. MCCOY.

REFERENCES CITEEI The following references are of record, in the file ofthis patent: 1 4

UNITED STATES PATENTS Number Name Date 1,529,607 Owen .'Mar. 10, 19251,616,973 MacClatchie Feb. 8, 1927 1,835,418 McHardy Dec. 8, 19312,092,843 Henderson Sept. 14, 1937 2,208,181 Eggleston July 16, 1940

